1. Technical Field
The present invention relates to a lane deviation prevention control apparatus of a vehicle that, when the vehicle is about to deviate from the traveling lane, actuates an actuator to thereby apply a yaw moment to the vehicle to prevent deviation from a lane.
2. Related Art
In recent years, various devices for supporting driving have been developed and put to practical use for vehicles. A lane deviation prevention control apparatus that prevents deviation from a lane is one of such devices. For instance, Japanese Unexamined Patent Application Publication (JP-A) No. H7-105498 discloses a technique of a traveling state determining device of an automobile that predicts a deviation state from a lane on the basis of a distance to a point of intersection of an estimated traveling path of a vehicle and a side edge of a line and on the basis of an angle formed by the estimated traveling path and the side edge at the point of intersection and performs automatic steering correction in order to prevent deviation on the basis of the prediction. JP-A No. 2008-195402 discloses a technique of a driving support device that, when a lane deviation determining unit determines that a traveling vehicle will deviate from a lane, applies warning torque to the vehicle and prevents lane deviation. The driving support device sets, on the basis of a maximum of the warning torque applied to the vehicle, a change rate of the warning torque to the maximum of the warning torque such that time until the warning torque reaches the maximum is fixed.
In the technique of the traveling state determining device disclosed in JP-A No. H7-105498, when a value of a change rate of a target turning amount applied to the vehicle in order to prevent vehicle deviation is a fixed value and a set target turning amount is abruptly output, a steering system and vehicle behavior suddenly fluctuate and give a sense of discomfort to a driver. Therefore, in JP-A No. 2008-195402, the change rate of the warning torque (the target turning amount) to be generated is changed to prevent the vehicle behavior felt by the driver from being increasing. However, only with the change of the change rate of the target turning amount, it is likely that not only suppression of vehicle behavior fluctuation but also deviation prevention for the vehicle is made difficult by being affected by change rate suppression, for instance, during deviation to an outer (inner) side of the curve or during deviation due to disturbance action.